Field of the Invention
The present invention relates to a charging member, a process cartridge, and an electrophotographic apparatus.
Description of the Related Art
In an electrophotographic image forming apparatus (hereinafter referred to as “electrophotographic apparatus”), charges are uniformly applied onto an electrophotographic photoconductor (hereinafter also referred to as “photoconductor”) by a charging member, and then an electrostatic latent image is formed on the photoconductor with laser light modulated by an image signal. Thereafter, the electrostatic latent image is developed with a charged toner, and then the toner image is transferred to a recording medium, such as paper, whereby a desired image is obtained.
As a transfer system of the electrophotographic apparatus, an intermediate transfer system is mentioned which includes performing primary transfer of a non-fixed primary toner image on the photoconductor to an electrophotographic transfer member, performing secondary transfer of the non-fixed toner image from the electrophotographic transfer member to a recording medium, and then transferring the toner image onto the recording medium.
With an increase in the process speed of the electrophotographic apparatus in recent years, toner which is not transferred in the primary transfer and remains on the photoconductor (hereinafter referred to as “untransferred toner”) is likely to adhere to the surface of the charging member at an abutment portion between the photoconductor and the charging member. As a result, density unevenness sometimes arises on the image due to the adhering untransferred toner.
Japanese Patent Laid-Open No. 2007-004102 describes that a charging member having a resin layer containing polysiloxane having an alkyl fluoride group and an oxyalkylene group is effective for suppressing the toner adhesion because the surface free energy and the coefficient of friction of the charging member are low.